There are a lot of caches listed on the challenge checker map that are not challenges as such, they just have the word challenge in the cache name. I see no way of automating their removal, but could someone not remove them manually? A map of challenge caches should be exactly that.

Not impossible at all but thanks for your condescending reply. There are bookmarks kept up to date on geocaching.com which have all the UK's challenge caches on. I'm sure someone would be able to utilise those.

I agree and I think it is feasible to crowdsource the process (not just have one person do it!)

There are a number of people such as vogelbird and target who are very active at attempting to create a challenge checker for every challenge cache (at least in the areas they are interested in) when I have time I like to as well (though that is much rarer). It is often the case you'll come across a cache which isn't a challenge. At this point a simple mechanism as such to have it excluded from being counted as a challenge cache would be fantastic (adding a new tag against the cache in the DB). Similarly there could be a way to manually add a tag to other caches which are actually challenges despite not saying 'challenge' in them. This information could also be exposed in the api making it possible (and simple) to exclude challenges from being used in other challenges (a common requirement).

I'd agree there are other things that a higher priority as well. Good to know it is coming - as I mentioned when it does get done would be good to have the info available in the api as well to allow challenges to include/exclude challenges